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/*

 * Virtio Serial / Console Support

 *

 * Copyright IBM, Corp. 2008

 * Copyright Red Hat, Inc. 2009, 2010

 *

 * Authors:

 *  Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

 *  Amit Shah <amit.shah@redhat.com>

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 */

#ifndef _QEMU_VIRTIO_SERIAL_H

#define _QEMU_VIRTIO_SERIAL_H

#include "qdev.h"

#include "virtio.h"

/* == Interface shared between the guest kernel and qemu == */

/* The Virtio ID for virtio console / serial ports */

#define VIRTIO_ID_CONSOLE                3

/* Features supported */

#define VIRTIO_CONSOLE_F_MULTIPORT        1

#define VIRTIO_CONSOLE_BAD_ID           (~(uint32_t)0)

struct virtio_console_config {

    /*

     * These two fields are used by VIRTIO_CONSOLE_F_SIZE which

     * isn't implemented here yet

     */

    uint16_t cols;

    uint16_t rows;

    uint32_t max_nr_ports;

} __attribute__((packed));

struct virtio_console_control {

    uint32_t id;                /* Port number */

    uint16_t event;                /* The kind of control event (see below) */

    uint16_t value;                /* Extra information for the key */

};

struct virtio_serial_conf {

    /* Max. number of ports we can have for a virtio-serial device */

    uint32_t max_virtserial_ports;

};

/* Some events for the internal messages (control packets) */

#define VIRTIO_CONSOLE_DEVICE_READY        0

#define VIRTIO_CONSOLE_PORT_ADD                1

#define VIRTIO_CONSOLE_PORT_REMOVE        2

#define VIRTIO_CONSOLE_PORT_READY        3

#define VIRTIO_CONSOLE_CONSOLE_PORT        4

#define VIRTIO_CONSOLE_RESIZE                5

#define VIRTIO_CONSOLE_PORT_OPEN        6

#define VIRTIO_CONSOLE_PORT_NAME        7

/* == In-qemu interface == */

typedef struct VirtIOSerial VirtIOSerial;

typedef struct VirtIOSerialBus VirtIOSerialBus;

typedef struct VirtIOSerialPort VirtIOSerialPort;

typedef struct VirtIOSerialPortInfo VirtIOSerialPortInfo;

/*

 * This is the state that's shared between all the ports.  Some of the

 * state is configurable via command-line options. Some of it can be

 * set by individual devices in their initfn routines. Some of the

 * state is set by the generic qdev device init routine.

 */

struct VirtIOSerialPort {

    DeviceState dev;

    VirtIOSerialPortInfo *info;

    QTAILQ_ENTRY(VirtIOSerialPort) next;

    /*

     * This field gives us the virtio device as well as the qdev bus

     * that we are associated with

     */

    VirtIOSerial *vser;

    VirtQueue *ivq, *ovq;

    /*

     * This name is sent to the guest and exported via sysfs.

     * The guest could create symlinks based on this information.

     * The name is in the reverse fqdn format, like org.qemu.console.0

     */

    char *name;

    /*

     * This id helps identify ports between the guest and the host.

     * The guest sends a "header" with this id with each data packet

     * that it sends and the host can then find out which associated

     * device to send out this data to

     */

    uint32_t id;

    /*

     * This is the elem that we pop from the virtqueue.  A slow

     * backend that consumes guest data (e.g. the file backend for

     * qemu chardevs) can cause the guest to block till all the output

     * is flushed.  This isn't desired, so we keep a note of the last

     * element popped and continue consuming it once the backend

     * becomes writable again.

     */

    VirtQueueElement elem;

    /*

     * The index and the offset into the iov buffer that was popped in

     * elem above.

     */

    uint32_t iov_idx;

    uint64_t iov_offset;

    /*

     * When unthrottling we use a bottom-half to call flush_queued_data.

     */

    QEMUBH *bh;

    /* Is the corresponding guest device open? */

    bool guest_connected;

    /* Is this device open for IO on the host? */

    bool host_connected;

    /* Do apps not want to receive data? */

    bool throttled;

};

struct VirtIOSerialPortInfo {

    DeviceInfo qdev;

    /* Is this a device that binds with hvc in the guest? */

    bool is_console;

    /*

     * The per-port (or per-app) init function that's called when a

     * new device is found on the bus.

     */

    int (*init)(VirtIOSerialPort *port);

    /*

     * Per-port exit function that's called when a port gets

     * hot-unplugged or removed.

     */

    int (*exit)(VirtIOSerialPort *port);

    /* Callbacks for guest events */

        /* Guest opened device. */

    void (*guest_open)(VirtIOSerialPort *port);

        /* Guest closed device. */

    void (*guest_close)(VirtIOSerialPort *port);

        /* Guest is now ready to accept data (virtqueues set up). */

    void (*guest_ready)(VirtIOSerialPort *port);

    /*

     * Guest wrote some data to the port. This data is handed over to

     * the app via this callback.  The app can return a size less than

     * 'len'.  In this case, throttling will be enabled for this port.

     */

    ssize_t (*have_data)(VirtIOSerialPort *port, const uint8_t *buf,

                         size_t len);

};

/* Interface to the virtio-serial bus */

/*

 * Individual ports/apps should call this function to register the port

 * with the virtio-serial bus

 */

void virtio_serial_port_qdev_register(VirtIOSerialPortInfo *info);

/*

 * Open a connection to the port

 *   Returns 0 on success (always).

 */

int virtio_serial_open(VirtIOSerialPort *port);

/*

 * Close the connection to the port

 *   Returns 0 on success (always).

 */

int virtio_serial_close(VirtIOSerialPort *port);

/*

 * Send data to Guest

 */

ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,

                            size_t size);

/*

 * Query whether a guest is ready to receive data.

 */

size_t virtio_serial_guest_ready(VirtIOSerialPort *port);

/*

 * Flow control: Ports can signal to the virtio-serial core to stop

 * sending data or re-start sending data, depending on the 'throttle'

 * value here.

 */

void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);

#endif